grep

Use this command to search for information in a file or files. For example, suppose that we have a file dict whose contents are

   red rojo
  green verde
  blue azul
  white blanco
  black negro

Then we can look up items in our file like this;

   % grep red dict
    red rojo
  % grep blanco dict
    white blanco
  % grep brown dict
  %

Notice that no output was returned by grep brown. This is because "brown" is not in our dictionary file.

Grep can also be combined with other commands. For example, if one had a file of phone numbers named "ph", one entry per line, then the following command would give an alphabetical list of all persons whose name contains the string "Fred".

   % grep Fred ph | sort
    Alpha, Fred: 333-6565
    Beta, Freddie: 656-0099
    Frederickson, Molly: 444-0981
    Gamma, Fred-George: 111-7676
    Zeta, Frederick: 431-0987

The symbol "|" is called "pipe." It pipes the output of the grep command into the input of the sort command.

For more information on grep, consult

   % man grep